Control means for an inductance means

ABSTRACT

A resonant control means causes the voltage and current of an inductance drive means to be out of phase with each other so as to prevent operation of the inductance drive means.

Jan. 2, 1973 nit'ed States Patent 1191 Schmidgall [54] CONTROL MEANS FORAN 2,478,622" 1/1947 Morrison...................,..........

INDUCTANCE MEANS 2,435,423 2/1948 Clapp 3,491,458 1/1970 Elders eta1.... [75] inventor: Phillip L. Schmldgall, Indianapolis, 3,521,3767/1970 Be11er.... Ind. 3,540,131 11/1970 Kahale 3,613,254 101971 S 731Assignee: P. R. Mallory & Co. Inc., Indianapollsi PrimaryExaminer-Carroll B. Dority, Jr.

Attorney-Richard 1-1. Childress, Robert F. Meyer and Henry W. Cummings[22] Filed: Feb. 10, 1971 211 App]. No.: 114,140

ABSTRACT A resonant control means causes the voltage and current of aninductance drive means to be out of phase [58]Fieldo1Search..............

with each other so as to prevent operation of the inductance drivemeans.

8 Claims, 1 Drawing Figure Cooley PATENTEDmz ma INVENTOR. PHILLIP L.SCHMIDGALL /FM 67%.,

ATTORNEY CONTROL MEANS FOR AN INDUCTANCE MEANS This invention relates toa control means; more particularly, it relates to a control means whichselectively energizes and de-energizes an inductance means such as asynchronous motor. The invention is particularly useful in selectivelyenergizing and de-ener gizing the motor of an automatic clothes dryer.

The tumbling mechanism of an automatic clothes dryer is usually drivenby a suitable motor. The on-off operation of such a motor is usuallycontrolled by a cam programming means which is driven by a timer motor.A sensing means is provided to sense an operating condition of the dryersuch as the humidity in the tumbling mechanism which in turn regulatesthe on-off operation of the timer motor to which the cam programmingmeans is responsive. Energizing the timer motor operates the camprogramming means which turns off the dryer motor and thus stopsrotation of the tumbling mechanism of the dryer. Conversely, when thetimer motor is turned off, the dryer motor is allowed to operate undercertain conditions.

The present invention is concerned with a control means which includesan electrical circuit coupling the clothes dryerto the timer motor suchthat the timer motors on-off operation can be controlled in response toan operating condition of the dryer. In the present state of the art oftiming mechanisms, the motor driving the timing mechanism is usually ofthe synchronous motor type. A synchronous motor being an inductancemeans, the invention, in a more broader aspect, relates to control meanswhich includes an electrical circuit which operates or controls theon-off operation of an inductance means. i

it is, therefore, an object of the invention to provide a control meanswhich controls the on-off operation of an inductance means.

It is another object of the invention to provide a control means tocontrol the on-off operation of an inductance means which includes anelectrical circuit providing a resonant means which when energizedcauses the voltage-current phase relationship of the inductance means tobe out of phase in relation to each other such that the inductance meansdoes operate.

Still another object of the invention is to provide a resonant meanswhich when energized controls the voltage-current phase relationship ofan inductance means in the resonant means, the resonant means furtherincluding two capacitors connected in series, with the inductance meansconnected in parallel with one of the capacitors, and a control meansconnected in series with the inductance means.

Another object of the invention is to provide a control means whichincludes an electrical circuit having a resonant means and an electricalcurrent control phase means which cooperates with the resonant means toselectively energize and de-energize the resonant means.

Still another object of the invention is the provision of a controlmeans controlling the operation of an inductance means which includes anelectrical circuit providing a resonant means and an electrical currentphase control means cooperating with the resonant means, the electricalcurrent phase control means including an electronic switching means.

Still another object of the invention is the provision of thecombination of a motor driven dryer, a synchronous timer motor throughwhich a cam programming means controls the on-off operation of the motorfor the dryer, and a control means selectively energizing the timermotor, the control means with said timer motor including a resonantmeans which selectively causes the voltage and current of the timermotor to be out of phase with each other so as to prevent operation ofthe timer motor.

These and other objects of the invention will become apparent from thefollowing description taken in conjunction with the accompanying drawingwherein there is depicted a wiring diagram of the control means of thepresent invention shown in conjunction with the tumbling mechanism of anautomatic clothes dryer.

Generally speaking, the objects of the invention are accomplished byproviding in combination an a resonant means including an inductancemeans, and a means selectively energizing and de-energizing the resonantmeans, energizing the resonant means causing thevoltage and current ofthe inductance means to be out .of phase with each other so as toprevent operation of the inductance means. The resonant means is part ofan electrical circuit and includes two capacitors connected in series,with the inductance means connected in parallel with one of thecapacitors and a control means such as a diode connected in series withthe inductance means. Also included as part of the electrical circuit isan electrical current phase control means which includes a switchingmeans such as a silicon controlled rectifier and a biasing means whichin conjunction with a sensing means regulates the voltage to theswitching means. The sensing means may be connected to a suitableappliance such as an automatic clothes dryer to automatically controlthe on-off operation of the dryer.

Referring now to the drawing, there is shown portions of an automaticclothes dryer, namely, tumbling means 10 which includes a drum 11rotatably carried by a mounting rim 12. Mounting rim 12 is carried by asuitable frame 14 of the clothes dryer. The tumbling means 10 isrotatably driven through a suitable motor 16. The clothes to be driedare tumbled in the tumbling means 10. An operating condition of thedryer, such as the humidity inside the tumbling means, is sensed throughsensing means 18. Sensing means 18 includes sensor elements S, andScarried on the rim through suitable means such as electricallyinsulative support means 20 and 22. Suitable sensing elements wouldinclude plated electrodes, for example. A timer motor 24 rotatablydrives a cam programming means 26 which includes at least one cam 28 andan electrical switch responsive to the cam. As will be hereinafterdescribed, the on-off operation of the motor 16 is responsive to the cammeans 26 through the switch that is driven by the timer motor 24. Theon-off operation of the timer motor 24 is controlled through controlmeans 30 which includes an electrical circuit 32. Electrical circuit 32includes resonant means 34 and electrical current phase control means36, sensing means 18 being included as part of the electrical currentphase control means. The resonant means 34, when energized, will, ashereinafter described, cause the voltage and current of the motor 24 tobe out of phase with each other so as to prevent operation of the motor.The resonant means includes capacitors C, and C, connected in seriesbetween terminals L, and L, with motor 24 being connected in parallelwith capacitor C, and a control means 38 connected in series with themotor 24. Control means 38 includes diode D,. Terminals L, and L, may beconnected to any suitable AC power source. Electrical current phasecontrol means 36 includes a switching means 40, a biasing means 42 andsensing means 18. Biasing means 42 includes resistor R, in series withdiode D, which is in series with triggering means 44 which is in serieswith resistors R and R, in combination with capacitor C, which activatesthe trigger means 44. Capacitor C, is connected in parallel acrossresistor R,. This series combination is connected from one end of themotor 24 to the line L,. Triggering means 44 includes a neon lamp N,.Switching means 40 includes a silicon controlled rectifier (SCR) whichis connected anode to motor, cathode to the line, and gate to thejunction of R, and R To complete the description, resistor R, is inseries with sensing elements S, and 8,, this combination being inparallel with capacitor C Diode D, is connected in series to motor 24,cathode to motor and anode to line L,, the combination being in parallelwith capacitor C,,.

In operation, assume that wet clothes are placed in drum 11 of thedryer. The humidity in the drum is sensed by sensing elements S, and S,.The wet clothes in the dryer keep capacitor C, from charging; thuskeeping neon tube N, from conducting which in turn keeps SCR fromconductingfln this condition, C, and C, are in series across the line L,and L,, the motor 24 is in series with diode D,, both being in parallelwith C,. On the first positive half cycle, C, and C, are charged whileno current flows through the motor 24 due to the diode D,. On thenegative half cycle, C, and C, are discharged and recharged in theopposite direction and current flows through the motor 24. However,current. I

lags voltage in an inductance means such as a synchronous motor andleads voltage in a capacitor. Therefore, the current through the motor24 and capacitance are out of phase causing the voltage across the motorto be nearly zero. With capacitor C, included in the circuit, thevoltage across the motor 24 becomes zero due to the additional lead ofcurrent with respect to voltage in C, I

As the clothes become dryer, the electrical resistance of the clothesincreases. When the resistance of the clothes becomes sufficiently high(greater than approximately 80,000 ohms, for example), capacitor C,,will charge on the positive half voltage cycle through capacitor C,,motor 24, resistor R, and diode D,. When the voltage across capacitor C,becomes large enough, neon lamp N, will start conducting throughresistor R and R The current through resistor R, will produce a voltageat the gate of the SCR which will cause the SCR to conduct in theforward direction for the remainder of the positive half cycle. Duringthe negative half cycle, diode D, conducts. When the SCR and diode D,are conducting, approximately 300 of the 360 electrical degress ofvoltage appear across the motor 24 and the motor will run. Capacitor C,increases the power delivered by the motor when the motor is in therunning condition. The synchronous motor 24 will turn the camprogramming means which will turn off the dryer motor. claim:

1. In combination, a motor driven dryer, a synchronous motor and camprogramming means responsive to said synchronous motor, said camprogramming means in cooperation with switch means selectivelyenergizing and de-energizing said dryer motor, and an electrical circuitcomprising: I

a. terminal means connecting said electrical circuit to an alternatingcurrent power source,

b. resonant means including said synchronous motor,

c. electrical current phase control means cooperating with said resonantmeans including sensing means responsive to an operating condition ofsaid dryer,

energizing said electrical current phase control means energizing saidresonant means and causing the voltage-current phase relationship ofsaid ,synchronous motor to be out of phase relation to each other suchthat said synchronous motor does not operate.

2. The combination according to claim 14 wherein said resonant meansfurther includes at least two capacitors connected in series betweensaid terminal means, said synchronous motor connected in parallel withone of said capacitors and a control means connected in series with saidsynchronous motor.

3. The combination according to claim 2 wherein said control means is adiode.

4. The combination according to claim 14 wherein said electrical currentphase control means includes a switching means, a biasing means, saidsensing means regulating the voltage to said switching means.

5. The combination according to claim 4 wherein said sensing meansincludes electrode means disposed in a drum of said clothes dryer and acurrent limiting means in series with said electrode means.

6. The combination according to claim 4 wherein said biasing meansincludes a series combination of resistors, diode means and triggermeans in combiantion. with a capacitor to activate said trigger means.

7. The combination according to claim 6 wherein said trigger meansincludes a neon light.

8. The combination according to claim 4 wherein said switching meansincludes a silicon controlled rectifier.

4K 10K i i 4'

1. In combination, a motor driven dryer, a synchronous motor and camprogramming means responsive to said synchronous motor, said camprogramming means in cooperation with switch means selectivelyenergizing and de-energizing said dryer motor, and an electrical circuitcomprising: a. terminal means connecting said electrical circuit to analternating current power source, b. resonant means including saidsynchronous motor, c. electrical current phase control means cooperatingwith said resonant means including sensing means responsive to anoperating condition of said Dryer, energizing said electrical currentphase control means energizing said resonant means and causing thevoltage-current phase relationship of said synchronous motor to be outof phase relation to each other such that said synchronous motor doesnot operate.
 2. The combination according to claim 14 wherein saidresonant means further includes at least two capacitors connected inseries between said terminal means, said synchronous motor connected inparallel with one of said capacitors and a control means connected inseries with said synchronous motor.
 3. The combination according toclaim 2 wherein said control means is a diode.
 4. The combinationaccording to claim 14 wherein said electrical current phase controlmeans includes a switching means, a biasing means, said sensing meansregulating the voltage to said switching means.
 5. The combinationaccording to claim 4 wherein said sensing means includes electrode meansdisposed in a drum of said clothes dryer and a current limiting means inseries with said electrode means.
 6. The combination according to claim4 wherein said biasing means includes a series combination of resistors,diode means and trigger means in combiantion. with a capacitor toactivate said trigger means.
 7. The combination according to claim 6wherein said trigger means includes a neon light.
 8. The combinationaccording to claim 4 wherein said switching means includes a siliconcontrolled rectifier.